This invention relates to portable ECG data-storage apparatus, and more particularly to such which is capable of recording, transporting, and playing back, conveniently, multiple-lead ECG data.
In the field of cardiology, wherein many devices in recent years have been introduced to improve the acquiring, handling, and analysis of ECG data, there remains a need for the availability of a compact, portable ECG data-recording device which is capable of recording multiple-lead analogue signals made available by a conventional ECG machine for later playback, broadcast (via telephonic transmission, etc.), and analysis at some other location.
Hand-held ECG recorders which are now available that, themselves, directly attach to the human body to take in and record an ECG signal, have very limited storage capacity, and are not suitable for acquiring and holding multiple-lead (such as 12-lead) ECG data. Too much time is required in the process of switching from lead to lead, and for allowing signal stabilization to occur, to make easily portable a device having a memory capacity sufficiently large to allow all of this activity.
An important object of the present invention is to address this situation by offering an ECG data-storage device which does not attach directly to the human body, but rather, receives its input signal from the analogue output terminals of a conventional ECG machine which itself is attachable to a patient's body.
The proposed device, under operator control, offers successive, flagged, time windows during which it is capable of recording and storing the analogue EC signals supplied to it from such an external machine. Memory utilization does not occur except during these time windows, and only after an operator signals the device that a new lead is in place, and that signal stabilization (as, for example, is determined by looking at a strip chart) has bee achieved. While different time windows might be selected, one that has been found to be particularly useful is a 5-second time window.
The device is equipped with suitable analogue/digital conversion apparatus, whereby such an analogue signal is converted into digitally recorded data for later playback. Playback can occur, according to the invention, either directly back to an artifact of the originally recorded analogue signal, for recoupling to an ECG machine for strip chart reporting, etc., and/or can be played out audibly for a user to hear, or in a suitably frequency-coded form for transtelephonic transmission to a remote location.
The device proposed by the invention is capable of handling up to a full 12-lead collection of data, with each time-windowed record in memory suitably flagged so that it is readily identifiable later during playback. The semiconductor memory which is provided to afford such a storage capacity is capable, in the device disclosed herein, of storing up to about 60-seconds of real-time information.
Compactness and portability characterize the proposed device, in that it can easily take the form, shape and size of a conventional hand-held dictation recorder.
These and other objects and advantages which are attained by the invention will become more fully apparent as the description which now follows is read in conjunction with the single drawing figure.